In recent years, a polymerizable liquid crystal compound is used for a film having optical anisotropy. The compound has optical anisotropy in a liquid crystal state, and the orientation of the liquid crystal compound is fixed through polymerization. The addition of an optically active compound to a polymerizable liquid crystal compound or composition induces a helical structure, and the compound or composition has various applications depending on the helical pitch.
Examples of the application utilizing selective reflection of visible light include a design application including ornamental members and an application to a color filter used in a liquid crystal display device. Furthermore, an application to anticounterfeit technologies is also included since reflected light and transmitted light have peculiar metallic gloss and variation in color depending on viewing angles, and these optical characteristics cannot be duplicated with an ordinary duplicator. Moreover, such a brightness enhancing film is also proposed by utilizing a circularly polarized light separating function that has a polarizing plate laminated thereon a ¼ wavelength plate and an optically anisotropic film exhibiting a circularly polarized light separating function. These applications demand a circularly polarized light separating function over the whole visible light region (a wavelength range of from 350 to 750 nm), for which plural layers with different pitches are laminated, or the pitch is continuously changed in the thickness direction (see Patent Documents 1 and 2). Such a reflection film is also proposed that has a reflection wavelength range set at an near infrared region (a wavelength range of from 800 to 2,500 nm) (see Patent Document 3).
The inventors have provided a polymerizable liquid crystal composition exhibiting twisted orientation containing a polymerizable liquid crystal compound having an epoxy group and an oxetanyl group as a polymerizable group with an optically active compound (see Patent Document 4). Simplification in production process is expected since the polymerizable liquid crystal composition can be cured in the air, but there are some cases depending on the combination of polymerizable liquid crystal compounds where orientation defects occur in the drying step after coating to a supporting substrate, thereby causing a problem, such as appearance failure.    Patent Document 1: JP-A-2003-84269    Patent Document 2: JP-A-2005-345982    Patent Document 3: JP-A-2004-333671    Patent Document 4: JP-A-2005-263778